A Japanese daily says Ko Yong-hee, wife of North Korean leader Kim Jong-il, is terminally ill with breast cancer, and Pyongyang seems to be preparing for her death.

The Sankei Shimbun newspaper said Wednesday that the North Korean government has purchased an "extremely expensive" coffin in Paris, where 51-year-old Ko had received cancer treatment earlier this year. Apparently related to Ko's illness, the coffin was transported to Pyongyang via a chartered flight following her return to the North.

Ko, referred to as the "revered mother" in North Korea, is the mother of the second and third sons of Kim Jong-il.